We propose to continue our investigation of integrative mechanisms which regulate transcription and translation: (A) We will continue to study the effects of a newly discovered effector molecule, ppGp, on transcription in E. coli. (B) We have demonstrated that Bacillus subtilus produces several different 3' modified adenine and guanine nucleotides during the stringent response; we propose to test the effect of these putative regulators on rRNA and tRNA synthesis. (C) We will attempt to isolate and identify the product of the relX gene, which is involved in the coupling of ppGpp synthesis with energy metabolism. (D) We will continue our studies of RelA mistranslation, and of the kinetics of error propagation; in the latter case, we propose to extend our studies to eukaryotic organisms, so as to test the theory that error propagation may contribute to senescence of somatic cells.